One almost certainly will encounter inhibited sexual desire and, possibly, true sexual aversion. True sexual aversion is infrequently encountered. It is modified by neurotransmitters and hormones.

Sexual desire is an urge that motivates women (and men) to seek out, intimate, and engage in sexual activity. But sexual desire is not merely a subjective sensation or simply a cognitive event. It is modified by social behaviour, as well as by neurotransmitters and hormones. For example, women generally have a higher level of sexual interest at the midpoint of their cycle, when production of sex hormones is at their peak.

A landmark study (1985) on sex hormones divided women whose ovaries had been removed into four groups. Each one of four types of medication: estrogen, testosterone, a combination, or a placebo (Sherwin). The groups on testosterone reported an increased level of desire, arousal, and sexual fantasizing, while those on estrogen or a placebo did not. Testosterone, according to this study and others since (North American menopause Society 1998), is the hormone behind sexual desire. By contrast estrogen’s role is more closely connected to physical aspects of sexuality, such as vaginal lubrication, other arousal responses, and orgasm (Sarrel 1990). Estrogen mediates these responses through receptor sites on the nerves that supply the vagina, clitoris, and other pelvic structures. By contrast, testosterone mediates its effects directly on receptor sites in the brain. These studies and others have resulted in the increasing common use of testosterone to boost female sexual interest and fantasizing.